1. Field of the Invention
The present invention relates to a translucent front panel having near-infrared rays absorbing ability, and further electromagnetic shielding performance to be mounted at the front of a plasma display.
2. Description of Related Art
As a front panel for displays, various front panels with reflection reducing property, abrasion resistance, and stain proofing property have been proposed in order to prevent the indistinctness of the image due to the reflection of illumination light and the reflection of a background, protect the display surface, and proof the stain of the display surface.
A plasma display emits not only visible rays but also rays of light in so-called the near-infrared region of 800 to 1100 nm.
On the other hand, as disclosed in Japanese Non-examined Patent Publication No. 2-309508, the light in the near-infrared region around 950 nm has been used for a remote-control system such as a household fluorescent lamp, TV, and VTR. Further, the light in the same region has been used for data communications between computers.
On the periphery of a plasma display, there has tended to occur trouble in the remote-control system and data communications in these devices, which is supposed to be caused by the light in the near-infrared region emitted from the plasma display.
A plasma display emits not only light in the near-infrared region but also electromagnetic wave, and hence a problem of malfunctions of peripheral devices due to the electromagnetic wave has been pointed out.
In Japanese Non-examined Patent Publication No. 6-118228, there is disclosed an optical filter suitable for photometric filters and color correction filters of cameras which contains a copolymer and a metallic salt. This copolymer is obtained by copolymerizing a monomer mixture which comprises a monomer containing a phosphoric acid group of a specific structure and a monomer copolymerizable with this monomer, and the metallic salt contains copper salts such as copper benzoate and copper acetate as a main component.
However, with conventional display front panels proposed in the prior art, which have reflection reducing property, abrasion resistance, and stain proofing property, the trouble to remote-control system and data communications, and further the effect on the peripheral devices due to electromagnetic wave cannot be prevented.
In Japanese Non-examined Patent Publication No. 6-118228, there is no description of a plasma display front panel.
From a detailed study of a front panel for a plasma display which is excellent in near-infrared rays absorbing ability and further electromagnetic shielding performance, the inventors of this invention have reached the present invention by founding as follows: the transparent substrate is suitable for a plasma display front panel which is produced by molding a resinous composition containing (a) a monomer having an unsaturated double bond and/or polymer thereof, (b) a phosphorus atom-containing compound, and (c) a copper atom-containing compound, and has a 50% or more average transmittance of light with a wavelength in the range of 450 nm to 650 nm, and a 30% or less average transmittance of light with a wavelength in the range of 800 nm to 1000 nm. Further, the one obtained by providing this transparent substrate with an electromagnetic shielding layer is suitable for a plasma display front panel. These substrates can protect the front of a plasma display, and exhibit excellent near-infrared rays absorbing ability and electromagnetic shielding performance.